Exhaust vents have been provided for dryers for several years. Commonly, the exhaust vent includes a type of flapper valve which prevents cold air or hot air from entering the house through the dryer vent. An example of a dryer vent with flapper valve is described in U.S. Pat. No. 4,967,490. However, with the exterior vent animals can still enter the vent area and nest in those areas. U.S. Pat. No. 5,547,422 describes a cage-like guard which may be placed over the vent to preclude animals from entering the vent and nesting in the vent opening. However that system is quite bulky and can be damaged since it is mounted on the exterior of the home.
Protective grills or screens have been mounted in the exhaust vent, such as described in Canadian patent 2,111,157 and U.S. Pat. No. 5,046,408. The protective screens are clip-mounted in the vent or mounted in narrow channels. These arrangements are cumbersome and usually break-down resulting in animals gaining access to the interior of the vent opening.
An attempt to overcome these problems has been provided with snap-fit type grills; for example, as described in Canadian patent application 2,232,659 and U.S. Pat. Nos. 5,722,181 and 5,916,023. Various arrangements are provided in snap-fitting the grill in place. In U.S. Pat. No. 5,722,181, the entire grill is snap-fitted to a base. However, it projects considerably from the exterior wall and can be readily knocked off. The grill of U.S. Pat. No. 5,916,023 is mounted at the base of the vent opening. However it is very difficult to remove from the exhaust vent hood, because the snap-fit projections engage the front wall of the hood. One has to use a screwdriver or the like to unclip the grill from the hood. This can result in breakage of the grill particularly at colder temperatures. The hinge-mounted grill, as described in Canadian patent application 2,232,659 is pivoted at its base and clips into the hood at its top. Again, particularly in cold weather, it is particularly difficult to disengage the grill. Normally a screwdriver is required to pry it out. When the grill falls down, it can be readily disengaged from its hinge connections which can result in breakage of the unit.
Applicant's invention overcomes a number of the above problems by providing a grill which is snap-fitted into a downwardly projecting opening of the vent hood, The grill interfits with the hood in a way that it can only be mounted in one direction in the hood. It can only be disengaged by squeezing the grill at its sides and thirdly, the detent system is arranged where such gentle squeezing of the grill provides for immediate disengagement of the grill from the hood.